Control system



Aug. 7, 1928.

' 1,680,259 a. L. SPENCER ET AL I CONTROL SYSTEM Filed Oct. 22, 1924 3Sheets-Sheet .1

EHWEMCER AL CONTROL SYSTEM Filed Oct. 22, 1924 3 shee'ts sheet 2 Aug. 7,1928. 1,680,259

G. L. SPENCER ET AL CONTROL SYSTEM vFiled Oct. 22, 1924 3 Sheets-Sheet 3G" 4 gnqfenkom Patented Aug. 7, 1928.

UNITED STATES 1,680,259 PATENT oFFIcE.

GUILFORD L. sPEN'cER, F :rmeriano, MATANZAS, AND vmem E. mE'rc'ALFE, 0E

DELICIAS, ORIENTE, CUBA;'EMMA F. sPEnoER, EXECUTRIX or sun oUI roRD L.SPENCER, DEoEAsEn, ASSIGNOR 'ro EMMA F, SPENCER.

CONTROL SYSTEM.

Application filed October-22, 19 24. Serial No. 745,241.

This invention relates broadly to the method of and apparatus for thecontrol of centrifugal separators, and has for its main object theprovision of means for measuring,

, limiting, or mea suringand limiting the application of centrifugalforce to such machines. More particularly, this invention relates to thecontrol of centrifugal sepa rators used in purging the sugars of themother liquor, and to the provision of means for applying, preferablyautomatically, a wash of water or other suitable substance to the purgedsugars at the proper time and in the proper quantity.

In the present practice of operating centrifugal machines, the operatormust Judge as to the proper time to stop .themachine and discharge thepurged substance, and he judges by the appearance of the substance,usually, and also is influenced by the time element. Obviously, thismethod of controlling the operation of the centrifugals is highlyinaccurate, and this is especially true because of the short timeconsumed by the cycle of necessary operations. For example, in treatinga high grade sugar magma or massecuite of moderate density in a moderncentrifugal separator of the self-discharging or bottomless type, thefull cycle of operations may not consume one hundred seconds. It wouldiequire about thirty seconds for starting, accelerating and charging thecentrifugal basket with magma, leaving seventy seconds for purging thesugar, switching off the current, applying the brakes and stopping themachine. Of this period of seventy seconds probable forty to fiftyseconds constitute the period during which the machine is exerting fullcentrifugal force. With suchji short cycle of operation, it is apparentthat the operator'must be very skillful as a small fraction of timeincorrectly estimated over or under the time necessary for the propertreatment. of the 4 magma will result in improperly treated sugar thatwill have unsatisfactory storage qualities and perhaps otherunsatisfactory.

characteristics. Further, if the. centrifugal machine is allowed tooperate too long, there 9 "results a wall of sugar so hard that it mustbe broken 1 down with a paddle and conse-v ly disadvantageous and thatit is practically very dlflicult, ifnot-impossible, to obtain a purgedproduct of even quality and proper character. The object of thisinvention, as broadly stated, is to obviate as far as possible the errorusual when human judgment is (]3XCIClSed and provide an automatic con-With the above main object in view, this invention provides electricallyoperated de vices which measure and limit the application of centrifugalforce to the. material treated so that when the machine is started itwill run exactly for that length of time duringwhrch ]ust the rightamount of energy having a, centrifugal force factor will be appliedtoyield a product of the proper character. When such amount of energy hasbeen applied, a wash is automatically and effectively applied to thematerial, and the; machine is automatically-stopped at the propermoment. While thisinvention contemplates the automatic operation of acontrol means'for the-purpose stated, there is also contemplated amanual control follow mg certainind-ications on a device providedtoundicatejust when the manual operations are to take place, this-manualcontrol being alternative to the automatic control. invention alsocontemplates certain provislons for adjustments to meet practical ope-1-ating conditionsas may be required.

For a complete understanding of the invention reference is to be had tothe following detailed description and to the accompanyingdrawings-forminga part. of this specification.

. In the drawings;

Fig. 1 is a diagrammatic view of the apparatus constituting .anembodiment of the invention;

Fig. 2 is a plan view of the energy measuring and limiting deviceconstituting an important feature of this invention;

Fig. 3 is a sectional view on the line 33 of Fig. 2;

Fig. 4 is a side elevational view of the measurin and limiting device;

Fig. 5 1s a diagrammatic view of the electro magnets used in themeasuring device;

Fig-.6 is a diagrammatic view of a modified measuring device 5 and Fig.7 is a diagrammat-ic view ofa ma er control.

The-

more particularly to Fig. 1,; there provided in connection with themotor M which drives .the centrifugal, the shaft G of which is shown theusual brake B. This driving and brake arrangement is well known and isshown conventionally as a detailed showing is not necessary.

A small alternating current generator G is associated with thecentrifugal shaft C and is driven thereby through anysuitable drivingconnection, preferably by the associated gears 11 and 12. The energy atunity power factor of the generator G is directly proportional to thecentrifugal effect of the centrifugal separator so that by measuring theenergy output of the generator G the total centrifugal effect on thesugar or other substance in the separator is measured. The energy outputof this generator can be measured by a watthour meter which is shown inFig. 1 and represented by the reference character 13. This watthourmeter is shown in a modified arrangement in Fig. 7 where the meter isdesignated by the reference character 13'. The meter shown by Fig. 1,generally, and by Figs. 2 to 5, in detail is a specially designed deviceand constitutes not only a meter but an energ limiting device as willhereinafter more fu 1y appear. It is apparent that since the metermeasures the energy output of the generator G which is proportional tothe centrifugal effect of the separator, the meter could be calibratedas shown by Fig. 7 so that the operator could stop the centrifugal whenthe meter gave the proper indication. It could also be marked so thatthe operator would apply the wash when the sugar had attained a certaindryness, and the meter would also indicate when the separator should bestopped. However, instead of this manual control following indicationsby the meter, it is proposed to control the centrifugal machinesautomatically in response to the energy output of the generator G.

As is already apparent from the foregoing discussion, the meter 13 whichmay preferably be termed an energy integrating device is a veryimportant feature of this in vention. Any generator and any watthourmeter that would measure the generator output at unity power factorwould be satisfactory, and while Fig. 1 shows a two phase generator anda special type-of meter or energy integrator shown in detail by Figs. 2to 5, as will be hereinafter described, the showing is to be consideredas general and not specific only to this special type of generator andintegrator.

A meter of the induction wattho'ur type musthave two sources of magneticflux. one

above and one below the meter disk, if accurate indications of energy atall power factors are to be given. These two sources of magnetic fluxmust be mechanically displaced by ninety electrical space degrees andthe two magnetic fluxes must differ in time phase by an angle whosecosine is equal'to the power factor. In this control system, thecentrifugal efiect is proportional to the square of the speed of thecentrifugal separator. An electric generator with a given fieldexcitation generates a voltage directly proportional-to the speed of thegenerator. In a two phase generator as shown by Fig. 1, there are twoequal voltages generated in two separate windings, these voltages beingninety degrees out of phase. A meter having two separate windings ofequal resistance and equal inductance furnishing excitation to twosources of magnetic flux mechanically displaced by "ninety degrees willmeasure the square of the voltage of the generator and. integrate thissquared voltage quantity for time and thus give a correct indication ofthe centrifugal effect.

In Fig. 1, the'two phase generator G has its field excited from aconstant D. C. source 14 and this generator furnishes excitation to thewindings 15? and 16'of the meter or integrator 13. Referring to Fig. 2,this integrator comprises two electromagnets 17 and 18 and a disk 19having associated therewith the usual brake magnet 20. The mechanicaland electrical arrangement of these magnets 17 and 18 are clearly shownby Fig. 5, and it will be seen that winding 15' which is excited by onephase of the generator G furnishes one source of flux and that windingl6 which is excited by the other phase of the generator furnishes theother source of flux, and that the two sources of flux are displacedmechanically by ninety degrees. This combination of two phase meter and.two phase generator will be accurate and independent of frequency, asthe meter is the sole load of the generator and each meter winding hasequal resistance and equal inductance and therefore the current in eachphase will lag behind its voltage by the same amount so that the fluxesfrom the two sources are ninety degrees apart regardless of frequency.The torque acting on the disk 19 will therefore be solely and directlyproportional to the square of thevoltage of the two phase generator G,which is proportional to the square of the speed of the centrifugalseparator.

The disk 19 is secured to a spindle 21 which is journalled in bearings22 and 23 secured in lower and upper brackets 24 and 25. respectively.These brackets are associated as shown with the magnet holding frames 26and 27. A counter spindle 28 is driven at reduced speed by the spindle21 through the reduction gears 29 and 30. The spindle 28 is journalledat its lower end in a bearing 31 supported from the bracket 25 and itsupper end in the upper end of the arm 37 which acts as a stop for thehand P,

and to the rings 34, 35, and 36 are secured the arms S, SWV, and W, resectively. In Fig. 1 there is a conventional s lowing of the rings andthe associated. arms, the same reference characters being used. It willthus be seen that as the spindle 21 is rotated motion is imparted to thecounter spindle 28 which actuates arm P which makes contact at certaintimes with arms'VV, SW, and S.

Referring now to Fig. 1 it will be seen that the contact of arm Pwithcontact arms W, SW, and S controls certain electrical circuits and byreferring to t-he diagram of connections shown by Fig. 1, the operationof the entire system will now be explained. Upon pressing the startbutton 38, the stop button'39 closing the circuit, a circuit iscompleted through magnet 40 which being energized closes the main'threepole switch 41 and also closes all the contacts, m m and m of the mainrelay MR. When the main switch 41 is closed the driving motor M startsand at the same time the brake solenoid 42 is energized, releasing thebrake band and permitting the centrifugal separator to accelerate tospeed. As the shaft C of the centrifugal separator rotates, thegenerator G delivers energy to the meter or energy integrator 13, thedisk 19 being thereby rotated to drive the, spindles 21 and 28, thespindle 28 actuatmg the arm P.' As the arm P moves it makes contact withthe contact arm W and thereby completes a circuit across the controlmains 43 which supply current preferably at 110 volts and cycles, thiscircuit being made through relay contacts (1 b and 121., all contacts ofmain relay MR being closed, and through solenoid A of relay AR. Whensolenoid A is thus energized, contact is made P at (1 a, and a. Thecontact at a now completes the circuit that at first went through P andW, and contact at a being now broken, the arm P may move from the arm WWithout any arcing since the circuit through these contact members hasalready till been broken. When relay contact a is closed, the valvesolenoid 44 is energized to attra t the valve operating arm 45 againstthe closing spring 46 to open the valve 47 whichpermits washing liquidto flow from the pipe 48 which will be properly;pos1- tioned in theventr iugal basket as 1 0bduring the travel of the arm P from thecontact W tothe contact SW. When the arm P makes contact with SW, acircuit across the line 43 is completed through the relay contacts bsolenoid B of relay BR, and relay contacts a of relay AR, a being closedat this time, whereupon relay contacts b and 6 open, and b closes, theopening of b and closing of b puts the solenoid B in a circuitindependent of'SW so that no arcing vious'. The solenoid-44remains-energized will occur when the arm P and contact SW separate. Assoon as 6 opens there is no circuit through solenoid A and relay con-,tacts of AR consequently open, .excepta which closes. As a opens thereis no circuit throughsolenoid B, and therefore-contact?) opens andcontacts 5 and 6 close. When contact a opens, valve solenoid'44 isdeenergized and spring 46 closes the valve 47. As contact arm Rcontinues to move, it makes contact with contact arm S and therebycompletes a circuit through solenoid C of relay CR across'the line 43.When solenoid C is ener ized, contacts a open to thereby open thec1rcuit.through the solenoid 40 and the main switch 41 consequentlyopens and likewise the relay contacts of main relay- MR also open, andthe brake solenoid 42 being tie-energized, permits the brake spring tobe applied to the brake band which quicklv brings the centrifugalmachine to a stop.

While the centrifugal machine is being stopped, the main contact arm Pis returned to zero position .against the fixed -stop 37 by'thepreferred means shown by Fig. 3. This arm returning means is preferablya weight w connected to the spindle 21 by a cord-49 which may be securedto a pulley 50 secured to the spindle 21, this cord passing over anidler pulley 51. The

weight w is just heavy enough to give sufiicient torque to effect thereturn of the arm P to the starting position in the time allowed for thecentrifugal machine to stop. The meter may be compensated for thecounter torque of the weight in the same way that the retarding effectof friction. is compensated for in watthour meters and for inductionmeters compensation could be -made following the principle of the shadedole. v

If a battery of centrifugal machines .isto be controlled, it might bedesirable to provide amaster control arrangement such, for example, asis shown diagrammatically by Fig. 6. Generators of the combination ofthe small-generator on he ce trifugal shaft a d'the -int r ait- G and G-are shown I as single phase generators and are supplied ing device. Thegenerator G1 will be driven as shown by Fig. 1 and will supply currentto a non-inductive load L which may be varied. The meter or energyintegrator 13' will measure the output of the generator G and aconventional watthour meter having a spindle 28 which may be arranged to.be driven by the spindle of the watthour the hand P as described inconnection with Figs.'1 to 5. It is'apparent that the use of a smallgenerator and an integrating meter or energy integrating device is animportant and the essential part of the system of control, but the typeof generator and the type of integrator is relatively uni important asthe method and apparatus may include generators and integrators of thealternating or direct current type.

Reverting to the master control for a battery of centrifugal machines,its operation may be readily understood considering the showings ofFigs. 6 and 7 together. In Fig. 7, the generator Gr corresponds to thegenerator Gr in Fig. 6. When it is necessary or desirable to change thelength of i the cycle of operations on a battery of controlledcentrifugal machines, each of which has been individually set by'meansof the individual adjustable load resistance L to i give the desiredproduct, the master control arrangement shown by Fig. 6 may be used. .Byadjusting the rheostat R the field excitation of all the generators G Getc., may be varied to vary the generated voltage to thereby vary thetime required for the hand P or P to move the required distance over,the scale S or to make the required contacts with contact arms IV, SW,and S. This master control in conjunction with the individual controlsgives a highly flexible control that adapts the system for use withcentrifugal machines treating various magmas.

For the sake of clearness and in order to disclose the invention so thatthe same could be readily understood, specific devices and arrangementshave been described and illustrated. It is to be understood, however,that this invention is not limited to the specific means disclosed butmay be embodied in other ways that will suggest themselves, in view ofthis broad disclosure, to persons skilled in the art. that thisinvention is broadly new and it is desired to claim it as such so thatall such changes as come within the scope of the It is believed appendedclaimsare to be considered as part of this invention.

Having thus described our invention, what furnishing energy to saidenergy responsive means in proportion to the energy developed by saidrotary machine.

2. In a control system for rotary machines, means for generating energyin proportion to the energy of the rotary machine, and means responsiveto the energy of said generating means for controlling the operation ofthe .rotary machine. I

3. In a control system for centrifugal separators, an electric generatorassociated with the centrifugal separator and delivering energy inproportion to the energy developed by the centrifugal separator, andmeans responsive to said electric generator energy for controlling theoperation of the centrifugal sepa-rzitor.

4.. In a control system, a driven machine, means for generating energyin direct pro portion to the energy generated by said ing said shaft, anelectric generator associated' with said shaft, means for receiving andintegratin the energy delivered by said genera-tor, an means associatedwith said integrating means for stopping said electric motor.

6. In a control system for centrifugal machines, an electric generatorassociated with 'a centrifugal machine and delivering energy inproportion to the energy developed. by the centrifugal machine, andmeans for integrating the electrical energy.

7. In combination with a driven machine, means for generating anddelivering energy in proportion to the energy developed by the machine,and means responsive to said generated energy for stopping said machine.

8. In combination, a rotary machine, a two phase electrical generatordriven thereby, means for integrating the energy of said generator,compri=ing two separate windings excited separately from the two phasesof the generator,- a disk actuated by the current generated therein bythe action of the fluxes having said windings as sources, and meansactuated by said disk for controlling the operation of said rotarymachine.

9. In a control system, a driven machine, means for generating ener indirect pro portion to the energy generated by said driven machine, andmeans responsive to said generated energy for stopping said drivenmachine.

10. The method of controlling the operation of a rotary machinecomprising furnishing energy to an energy responsive device inproportion to the energy developed by the machine and stopping saidmachine after said energy responsive device has consumed a predeterminedamount of energy.

11. The combination with a rotary machine, of means for generatingenergy in proportion to the square of the velocity of said rotatingmachine, and means actuated by the energy of said generating means forstopping said machine.

12. The combination With a rotary machine, of a two phase generatordriven'there- 15 by, and means actuated in. proportion to the energy ofsaid generator for controlling the operation of said machine.

In testimony whereof, we hereunto aflix our signatures.

GUILFORD L. SPENCER. VIRGIL E. METCALFE.

